This invention relates to an apparatus for measurement of velocity of fluids, in particular to the measurement of wind speed. The invention has particular usefulness in the determination of two orthogonal components of the mean velocity of wind in limits between 5 cm/sec and 50 m/sec.
Techniques involving the use of a drag sphere have previously been employed for measurement both in air and water. However, these systems proved to be insufficiently sensitive in the low range of wind velocities where the dynamic force is relatively low due to the square root relation between the wind force and the wind velocity.
Furthermore, the instruments were not usable in the wide range of environmental conditions encountered in meteorological stations. Furthermore, these instruments were not easily de-iceable.